I have covered the energy and environment beat since 1985, when I discovered my college was discarding radioactive waste in a dumpster. That story ran in the Arizona Republic, and I have chased electrons and pollutants ever since, for dailies in Arizona and California, for alternative weeklies including New Times and Newcity, for online innovators such as The Weather Channel's Forecast Earth project, The New York Times Company's LifeWire syndicate, and True/Slant—the prototype for the new Forbes. I've wandered far afield—to cover the counterrevolutionary war in Nicaragua, the World Series Earthquake in San Francisco, the UN Climate Change Conference in Copenhagen. For the last several years I have also been teaching journalism and argument at the University of Chicago. Email me here: jeffmcmahon.com/contact-jeff-mcmahon/

How To Remove Radioactive Iodine-131 From Drinking Water

The Environmental Protection Agency recommends reverse osmosis water treatment to remove radioactive isotopes that emit beta-particle radiation. But iodine-131, a beta emitter, is typically present in water as a dissolved gas, and reverse osmosis is known to be ineffective at capturing gases.

A combination of technologies, however, may remove most or all of the iodine-131 that finds its way into tap water, all available in consumer products for home water treatment.

First, the standard disclaimers: Every government agency involved in radiation monitoring—the EPA, FDA, USDA, NRC, CDC, etc.—has stressed that the radiation now reaching the United States has been found at levels thousands of times lower than standards of health concern. When it found iodine-131 in drinking water samples from Boise, Idaho and Richland, Washington this weekend, the EPA declared:

An infant would have to drink almost 7,000 liters of this water to receive a radiation dose equivalent to a day’s worth of the natural background radiation exposure we experience continuously from natural sources of radioactivity in our environment.”

But not everyone accepts the government’s reassurances. Notably, Physicians for Social Responsibility has insisted there is no safe level of exposure to radionuclides, regardless of the fact that we encounter them naturally:

There is no safe level of radionuclide exposure, whether from food, water or other sources. Period,” said Jeff Patterson, DO, immediate past president of Physicians for Social Responsibility. “Exposure to radionuclides, such as iodine-131 and cesium-137, increases the incidence of cancer. For this reason, every effort must be taken to minimize the radionuclide content in food and water.”

No matter where you stand on that debate, you might be someone who simply prefers not to ingest anything that escaped from a damaged nuclear reactor. If so, here’s what we know:

Reverse Osmosis

The EPA recommends reverse osmosis water treatment for most kinds of radioactive particles. Iodine-131 emits a small amount of gamma radiation but much larger amounts of beta radiation, and so is considered a beta emitter:

Reverse osmosis has been identified by EPA as a “best available technology” (BAT) and Small System Compliance Technology (SSCT) for uranium, radium, gross alpha, and beta particles and photon emitters. It can remove up to 99 percent of these radionuclides, as well as many other contaminants (e.g., arsenic, nitrate, and microbial contaminants). Reverse osmosis units can be automated and compact making them appropriate for small systems.

However, EPA designed its recommendations for the contaminants typically found in municipal water systems, so it doesn’t specify Iodine-131 by name. The same document goes on to say, “Reverse osmosis does not remove gaseous contaminants such as carbon dioxide and radon.”

Iodine-131 escapes from damaged nuclear plants as a gas, and this is why it disperses so quickly through the atmosphere. It is captured as a gas in atmospheric water, falls to the earth in rain and enters the water supply.

Reverse osmosis works by forcing water through material with very tiny pores—as tiny as .0001 microns—so that almost nothing except water emerges on the other side. Almost nothing.

“Dissolved gases and materials that readily turn into gases also can easily pass through most reverse osmosis membranes,” according to the University of Nevada Cooperative Extension. For this reason, “many reverse osmosis units have an activated carbon unit to remove or reduce the concentration of most organic compounds.”

Activated Carbon

That raises the next question: does activated carbon remove iodine-131? There is some evidence that it does. Scientists have used activated carbon to remove iodine-131 from the liquid fuel for nuclear solution reactors. And Carbon air filtration is used by employees of Perkin Elmer, a leading environmental monitoring and health safety firm, when they work with iodine-131 in closed quarters. At least one university has adopted Perkin Elmer’s procedures.

Activated carbon works by absorbing contaminants, and fixing them, as water passes through it. It has a disadvantage, however: it eventually reaches a load capacity and ceases to absorb new contaminants.

Ion Exchange

The EPA also recommends ion exchange for removing radioactive compounds from drinking water. The process used in water softeners, ion exchange removes contaminants when water passes through resins that contain sodium ions. The sodium ions readily exchange with contaminants.

Ion exchange is particularly recommended for removing Cesium-137, which has been found in rain samples in the U.S., but not yet in drinking water here. Some resins have been specifically designed for capturing Cesium-137, and ion exchange was used to clean up legacy nuclear waste from an old reactor at the Department of Energy’s Savannah River Site (pdf).

Triple Threat

The best solution may be the one used routinely to treat water at the Savannah River Site. The process combines activated carbon, reverse osmosis, and ion exchange. If one doesn’t get the iodine-131, two others have a chance to capture the radiation through other means.

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My training is chemistry and I have to say your explanations are both sound and lucid. My training is not medicine but I am tempted to go against medical warnings and and have my kids take some potassium iodide tablets to prevent uptake of radioactive iodine.

Bob, thank you for bringing potassium iodide into the discussion. The Centers for Disease Control very strongly urges people NOT to take potassium iodide except as a last resort in an emergency situation, such as an accident at a reactor near you. Here’s more on that:

I agree. It is foolish and rash to take potassium iodide now. But it can’t be denied there is some amount of I-131 (and/or other stuff) floating around the atmosphere.

I recommend the best natural source of iodine, kelp, simplest in pill form..one capsule gives you well over 200% of your daily iodine level (an important mineral many people are deficient in anyway).

I bought a pretty big bottle on iherb.com for like $3 shipped using the code KOL885. Sure didn’t seem like a bad bet, even if it only reduced my risk of getting cancer by .01%…check them out.

I’ve been sprinkling a little bit on my baby’s porridge in the morning. It seems like a good idea.

Also consider getting a proper water filter – my Berkey was a great investment, and I was happy to read earlier today it is one of the few filters that actually removes i-131 (with activated charcoal).

Just a few thoughts. I recommend people taking particular pains to take care of themselves and to eat healthy over the coming months..foods like miso soup, spirulina, fresh greens, and just natural mineral rich fresh food.

Use your intuition if it’s a good day to go out or not.

This reactor is going to keep releasing radioactive steam 24/7 for at least the next several months – and the majority of it will be blowing east. We’ll be OK if we take the right precautions and take care of ourselves.

Best way to prevent uptake of radioactive iodine is to have the body already saturated with non-radioactive iodine (in the appropriate amount). Only human bodies that are deficient in iodine will uptake and store the radioactive iodine. (I learned about this from lectures of David “Avocado” Wolfe.)

Good information on how to remove radioactive properties from our drinking water. I would be really careful what I eat and drink because of the effects of radiation poisoning. I know the levels of radiation in rain water are high, even in the United States and Canada right now. I’m choosing to be safe rather than really sick.

I agree totally about using Reverse Osmosis and treating the water with natural additives. I’ve found an article that back up and expands this information.

To remove 99% of all radiation from drinking water is a 2 step process. 1) You need clean, exposed carbon such as that you can make from a oxygen starved fire. 2) Next you will need fine clay, such as can be found in the banks of rivers. Crushed carbon is mixed in the water to be purified. Its necessary to keep remixing this exposed carbon as it will float. You repeat this process at least 2 times. Next you use clean, fine clay. The wine making industry uses this same “clearing process” to clairify wine. This fine clay is mixed into your water sample and allowed to absorb so there are no clumps. You should have a clay-muddy solution now. I use a bucket with a handle so I can attach a rope and spin the bucket to help start to drive the suspended particles down. Allow this to sit for 24-48 hours covered. This clay cloud will slowly drop to the bottom of the bucket, pulling the inpurities out of solution. Pour or siphon the water off the top. I describe this technique in some detail on my website www.dew-drop.com .

I agree totally that potassium iodide is not a safe option for radiation exposure. There are many other safe alternatives that do work. Natural zeolite is one of the best natural substances to remove radiation from the human body. There are also natural foods, like kelp, sea vegetables, unprocessed sea salt that can also be of help. There is a pretty good list of natural foods and purification substances that can be of extreme value during high radiation exposure levels.

It absolutely sickens me to here the advice from our EPA… Good Grief, they know very well that reverse osmosis and Ion exchange will do so very little to remove any radionuclide from water. I was a plumbing contractor for 14 yrs. and I have installed literally 100′s of reverse osmosis and water softener’s… It is sooo ridiculus and absurd that I almost chocked while reading this. THE ONLY WAY YOU CAN FILTER OUT THE RADIO ACTIVE MATERIAL IS TO DISTILL THE WATER…

Hi Jeff, It will leave the water… A distiller is not like a media filtering system, the gas can escape. That’s not to say that it couldn’t re-accumulate if it were in an enclosed environment, (the majority of distiller’s are not air tight) but at the very least in would remove the majority of the radionuclide’s, therefore making it much safer to drink than R/O or a water softener which has NO type of filtering media whatsoever. Either way there is no FULL PROOF method for sterilization for radiation but by far a distillation method is the wisest and best method of all…